Around the edge of the mound runs an enclosure wall of stones lying on the ground edge to edge. A few of these are sculptured. The finest is a great stone which lies in front of the entrance and shows a well-arranged design of spirals and lozenges. There are also engravings on one of the stones of the chambers. These designs are in general more skilful than those of Lough Crew. They consist mainly of chevrons, lozenges, spirals, and triangles. The monuments we have so far described are all tombs. Ireland also possesses several stone circles. The largest are situated round Lough Gur, 10 or 12 miles south of Limerick. There was at one time a fine circle west of Lough Gur at Rockbarton, but it is now destroyed. On the eastern edge of the lough is a double concentric ring of stones, the diameter of the inner circle being about 100 feet. The rings are 6 feet apart, and the space between them is filled up with earth. In 1869 an excavation was made within the circle and revealed some human remains, mostly those of children from six to eight years old. Further north is a remarkable group of monuments known as the Carrigalla circles. The first is a plain circle (L) 33 or 34 feet in diameter, composed of twenty-eight stones. The space within them is filled up with earth to form a raised platform. At a distance of 75 feet are two concentric circles, diameters 155 and 184 feet respectively, made of stones 5 or 6 feet high. The space between the two circles is filled with earth. Within these is a third concentric circle about 48 feet in diameter made of stones of the same size. This group of three concentric circles we will call M. The line joining the centres of L and M runs in a direction of 29 deg. or 30 deg. west of north and passes through a stone (N) 8 feet high standing on the top of a ridge 2500 feet away. There are two other stones more to the west (O and P) in such a position that the line joining them (41 deg. west of north) passes through the centre of M, from which they are distant 860 and 1450 feet respectively. Further, a line through the centre of L and a great standing stone (Q) 2480 feet from it in a direction 10 deg. east of south passes through the highest point in the district, 1615 feet away and 492 feet in height. Mr. Lewis compares this group of monuments with that of Stanton Drew in Somersetshire. In both a line joining the centre of two circles passes through a single stone in a northerly direction, and there is in both a fixed line from the centre of the larger circle. Captain Boyle Somerville, R.N., finds that the line 29 deg. or 30 deg. west of north would mark the setting of Capella in B.C. 1600, or Arcturus 500 B.C.; he adds that the direction 41 deg. west of north would suit Capella in 2500 B.C. or Castor in 2000 B.C.